The present invention relates generally to propulsion of objects within lumens, and specifically to methods and devices for propelling medical instruments through the colon.
The use of an endoscope for examining a body cavity is well known in the art. The diagnostic and therapeutic advantages conferred by direct examination of the gastrointestinal tract with a flexible endoscope have made this method a standard procedure of modem medicine. One of the most common endoscopic procedures is colonoscopy, which is performed for a wide variety of purposes, including diagnosis of cancer, determination of the source of gastrointestinal bleeding, viewing a site affected by inflammatory bowel disease, removing polyps, and reducing volvulus and intussusception.
While colonoscopy is useful and effective, it is a difficult procedure for a physician to perform and is painful and occasionally dangerous for the patient. These problems stem from the need to push and steer the long, flexible colonoscope through the intestine by pushing it in from its proximal end, outside the body.
It would be desirable to provide a propulsion mechanism to push or pull the endoscope forward from its distal end, inside the body. A number of methods and devices have been proposed for this purpose, although none has achieved clinical or commercial acceptance.
U.S. Pat. No. 4,207,872 to Meiri et al., whose disclosure is incorporated herein by reference, describes a device and method for advancing an endoscope through a body passage utilizing multiple fluid-filled flexible protrusions distributed along an outer surface of a sleeve containing the endoscope. Alternately increasing and decreasing the fluid pressure within the protrusions advances the endoscope along a body passage. Each protrusion is in direct contact with an inner surface of the body passage and applies local contact pressure against this relatively small contact surface in order to propel the endoscope forward.
U.S. Pat. No. 3,895,637 to Choy, whose disclosure is incorporated herein by reference, describes a device able to move through a tubular organ by sequentially inflating and deflating first and second radially inflatable members. The inflation anchors the inflated member against a local region of the tubular organ, while air pressure in a longitudinally inflatable communicating part of the device moves the non-anchored part of the device longitudinally through the tubular organ. Sufficient contact pressure of the inflated member against a relatively small length of the tubular organ is required in order for the device to be able to progress through the organ. U.S. Pat. No. 3,895,637 has no provision to distribute the contact pressure over a larger area of the tissue against which it presses in order to generate longitudinal motion.
U.S. Pat. No. 4,321,915 to Leighton et al., whose disclosure is incorporated herein by reference, describes an everting tube device for introducing a tool into a body cavity using alternating steps of applying positive pressure to evert the tube and advance the tool, and applying a vacuum to pull the everted tube away from the tool so that an operator can retract the tool one half of the distance it advanced in the previous step. The operator using this device is required to manually withdraw the tool the prescribed distance during every pressure cycle in order to avoid causing the tool to advance too far beyond the tip of the everted tube.
U.S. Pat. No. 4,403,985 to Boretos, whose disclosure is incorporated herein by reference, describes a jet-propelled device for insertion into body passageways. Pressurized fluid is passed to the device from outside of the body and then ejected from an orifice in the device in one direction in order to propel the device in the opposite direction. The device of U.S. Pat. No. 4,403,985 thus generates propulsion by expelling material into the body passageway.
It is an object of some aspects of the present invention to provide an improved system and method for propelling an object within a lumen.
It is a further object of some aspects of the present invention to provide an improved propulsion mechanism for advancing an endoscope within a body cavity of a patient for purposes of examination, diagnosis, and treatment.
In preferred embodiments of the present invention, a probe containing an endoscopic instrument is advanced through the lower gastrointestinal tract of a patient by inflation of a flexible sleeve coupled to the probe. One end of the sleeve is anchored, typically at or adjacent to the patient""s anus. As the sleeve is inflated, preferably using a pressurized gas, the probe is propelled forward, and the sleeve is fed out gradually between the probe and the anus. The portion of the sleeve that is inflated expands radially outward and remains substantially stationary relative to the intestinal wall as long as it is inflated. Longitudinal motion of the sleeve relative to the wall generally occurs only at and adjacent to the probe itself. The probe is thus advanced easily, and trauma to the gastrointestinal tract is minimized. To remove the probe, the sleeve is deflated and is used to pull the probe back out through the anus.
In some preferred embodiments of the present invention, the sleeve is passed around the probe and everts as the probe advances. Preferably, the sleeve is folded over one or more resilient rings encircling the probe, wherein the rings most preferably comprise ring-shaped springs, which encircle the outer surface of the probe and are held against the probe by magnetic attraction. Inflating the sleeve advances the probe through the colon, causing the sleeve to unfold from the inside out. Thus, an external portion of the sleeve opens out only near the probe, while the rest of the external portion stays stationary.
In other preferred embodiments of the present inventions the sleeve is stored in a compact state, typically folded or rolled up, inside or immediately adjacent to the probe. Most preferably, the folded or rolled-up probe is stored in a recess in a proximal portion of the probe. As the probe advances, the sleeve feeds gradually out of its stored state and expands against the intestinal wall.
In some preferred embodiments of the present invention, the probe comprises a separate steering unit for easing over or around curves in the gastrointestinal tract and obstructions, such as blood clots, small deformations and other obstacles, so that the probe can move within the patient""s body while minimizing harmful contact and friction. The steering unit preferably works by gas or fluid pressure, most preferably as described in Israel Patent Application 125,397, which is assigned to the assignee of the present patent application and whose disclosure is incorporated herein by reference. Alternatively, other steering methods known in the art may be used.
In some preferred embodiments of the present invention, the probe comprises instruments for examination, diagnosis and treatment. Preferably, the instruments include an imaging device, most preferably a miniature video camera and light source, as are known in the art, which are used to capture endoscopic images. Means for operating the instruments and receiving data therefrom comprise wires, fiber-optic lines, or tubes which are coupled to the instruments and extend to an operator or to equipment outside of the patient, which operates the instruments and receives data therefrom. The wires, line or tubes preferably pass through the sleeve.
In preferred embodiments of the present invention, advancing the probe through the gastrointestinal tract by way of inflating the sleeve reduces or eliminates the necessity of applying mechanical force at a proximal end of the probe (outside the patient""s body) to insert the probe, as is required using conventional endoscopes. The present invention thus reduces or eliminates the necessity of applying concentrated, local pressure to any part the patient""s body, reduces or eliminates rubbing and friction between the unit or parts of it and the patient""s body, and avoids ejecting fluids or other materials into the body""s passageway.
There is therefore provided, in accordance with a preferred embodiment of the present invention, endoscopic apparatus which advances within a lumen, including:
a probe having distal and proximal ends; and
a flexible sleeve coupled proximally to the probe, which sleeve is inflated in order to propel the probe within the lumen.
Preferably, the probe includes an imaging device, which captures images inside the lumen.
In a preferred embodiment, the sleeve everts as the probe advances, wherein the sleeve is passes around an outer surface of the probe and everts over a retaining ring, which holds the sleeve against the outer surface of the probe. Preferably, the probe includes magnetic material, and wherein the retaining ring includes one or more metal springs, which are held against the probe by magnetic attraction thereto.
Further preferably, an outer portion of the sleeve, which has everted over the ring, is anchored so as to remain substantially stationary relative to a wall of the lumen.
In another preferred embodiment, a portion of the sleeve is held at the probe in a compact state and feeds out from the proximal end of the probe as the probe advances. Preferably, the probe has a recess adjacent to the proximal end thereof, which contains the sleeve in the compact state. Further preferably, the sleeve is anchored at a position proximal to the probe so that a portion of the sleeve that has been inflated, between the proximal position and the probe, remains substantially stationary relative to a wall of the lumen.
Preferably, the lumen includes a passage inside the body of a patient, most preferably a portion of the gastrointestinal tract.
There is also provided, in accordance with a preferred embodiment of the present invention, a method for propelling a probe within a lumen, including:
coupling a flexible sleeve to a proximal end of the probe; and inflating the sleeve to advance the probe through the lumen.
In a preferred embodiment, the sleeve everts as the probe is advanced, wherein coupling the sleeve includes passing the sleeve around an outer surface of the probe and folding the sleeve over a retaining ring, which holds the sleeve against the outer surface of the probe. Preferably, the method includes anchoring an everted, outer portion of the sleeve so as to remain substantially stationary relative to a wall of the lumen.
In another preferred embodiment, coupling the sleeve includes holding a portion of the sleeve in a compact state at the proximal end of the probe, so that the sleeve feeds out from the proximal end as the probe advances.
Preferably, the lumen includes the gastrointestinal tract of a patient.
The present invention will be more fully understood from the following detailed description of the preferred embodiments thereof, taken together with the drawings, in which: